Bobbing

[gigex]

So, this may just be all in my head but recently my FZ started doing this weird "bobbing" thing every couple meters. It's not losing power or suddenly accelerating (or at least neither of the two to a significant extent), I'm not hearing any weird noises from the engine etc, but once i start moving it's as if i keep riding over small bumps. At first I thought it was just bad roads, but then i started noticing it on the hiway, which, for the most part is pretty even.
 
She had a valve service last month (at the dealership), oil changed and chain lubricated last week (by me), tyres are pretty much brand new (2 months max, installed etc at the dealership), chain and sprocket are fine. The only thing i can think of are the spark plugs, but that isn't due to change for another 3k km. It's probably worth noting i have an ejk (m4 exhaust) so she's running richer than stock. Below is a small clip i recorded this evening. You may be able to see what i mean better. 
 
Things to note 1.) the knocking noise @ 0:12-0:16 is caused by my helmet strap flapping against my helmet (forgot to buckle it, pulling over shortly after i realized lol) 
  2.) @0:18 i go over an ACTUAL bump in the road 
 
[video src=https://www.youtube.com/watch?v=d--nahy5bt0&feature=youtu.be]
 

[mjh937]

I am having a hard time seeing what you are talking about from the video, but could it be an out of balance front wheel because the weight (if there was one) came off?

[bugeyes]

Check rims and tyres, also pressure
Check chain for stiff links or other damage

[jake]

Check rims and tyres, also pressure Check chain for stiff links or other damage

Yep when my Chain was over due for replacement the bike was running like crap and the chain made a ton of noise. Bought a DID chain and the thing is running like a new bike. if you are close to 10,000 miles your chain is due.
 

[Beemer]

The factory suspension on this bike is bouncy and on my bike I notice about every imperfection in the road. There are small imperfections you just don't see sometimes so I'm betting it's just that and nothing wrong with the bike. It seems to me if the bike were causing it it would bounce constantly and with rhythm but it doesn't look like it is.  Are you a light person? A new spring and heavier fork oil may help to smooth things out. It's hard to say anything without riding your bike. GL!
 

[gigex]

Check rims and tyres, also pressure Check chain for stiff links or other damage

Yep when my Chain was over due for replacement the bike was running like crap and the chain made a ton of noise. Bought a DID chain and the thing is running like a new bike. if you are close to 10,000 miles your chain is due.

 
 
Hmmmmm, well I'm well past 10k miles, but the chain isn't stretched and the teeth on the sprockets seem ok (not a very aggressive rider). Will take a look at the chain more closely later and see. Thnx for the advice guys. Will update if I find something

[jake]

Yep when my Chain was over due for replacement the bike was running like crap and the chain made a ton of noise. Bought a DID chain and the thing is running like a new bike. if you are close to 10,000 miles your chain is due.

Hmmmmm, well I'm well past 10k miles, but the chain isn't stretched and the teeth on the sprockets seem ok (not a very aggressive rider). Will take a look at the chain more closely later and see. Thnx for the advice guys. Will update if I find something

Yeah I waited till 20,000 ish and it was well over due. Chain might be too tight to loose ect... is it dirty do you take off the cover to clean the drive gear? Your drive gear and sprocket should be fine. Just some Ideas other wise its a fueling issue of some sort. Oh and is your air filter clean.  

[AlbatrossCafe]

I am at 15.3k miles. My chain was last adjusted at 600 miles. It was VERY lose (I could press nearly 2 links up against the chain guard) and it had been running like that for a couple thousand miles. I didn't have the issue the OP is describing though. Only negative was a loss in MPG. I was able to tighten it within spec. Don't think you need a new chain at 10k unless you haven't lubed it once...
 
@gigex how many miles were you at when you had your valve clearance serviced?

[jake]

I could not find anything on how many miles to know when a chain is bad, a good chain can last a long time. But my bike was running like poo because of my chain. I used some crapy lube on my last bike trip and i think it took its toll on my chain.

[gigex]

I am at 15.3k miles. My chain was last adjusted at 600 miles. It was VERY lose (I could press nearly 2 links up against the chain guard) and it had been running like that for a couple thousand miles. I didn't have the issue the OP is describing though. Only negative was a loss in MPG. I was able to tighten it within spec. Don't think you need a new chain at 10k unless you haven't lubed it once... 
@gigex how many miles were you at when you had your valve clearance serviced?

I did it at 41 500 km (manual says to do it at 42k km), i know thats alot more than 10k miles, but the chain/sprockets haven't shown any signs of significant wear. I'll update this post with a pic of them, maybe i'm a bad judge lol. I clean and lube my chain religiously. every 2 weeks max. I mainly use the bike for commuting.
 
I inspected the chain and sprocket last night and was unable to find anything. Slack was within spec, there was no debris around the front sprocket, rims/tyres seem fine.
Also, if it were something to do with chain/sprocket or even tyres/rims, wouldn't the "bob" be felt through each revolution of those? And felt more frequently as you increase speed? I feel it every 5 seconds or so regardless of speed or gear, but not at idle. 

[bugeyes]

I am at 15.3k miles. My chain was last adjusted at 600 miles. It was VERY lose (I could press nearly 2 links up against the chain guard) and it had been running like that for a couple thousand miles. I didn't have the issue the OP is describing though. Only negative was a loss in MPG. I was able to tighten it within spec. Don't think you need a new chain at 10k unless you haven't lubed it once... 
@gigex how many miles were you at when you had your valve clearance serviced?

I did it at 41 500 km (manual says to do it at 42k km), i know thats alot more than 10k miles, but the chain/sprockets haven't shown any signs of significant wear. I'll update this post with a pic of them, maybe i'm a bad judge lol. I clean and lube my chain religiously. every 2 weeks max. I mainly use the bike for commuting.  
I inspected the chain and sprocket last night and was unable to find anything. Slack was within spec, there was no debris around the front sprocket, rims/tyres seem fine.
Also, if it were something to do with chain/sprocket or even tyres/rims, wouldn't the "bob" be felt through each revolution of those? And felt more frequently as you increase speed? I feel it every 5 seconds or so regardless of speed or gear, but not at idle. 
 
Yes, it would be propotional to the speed in frequency

 

[hobbs]

I am at 15.3k miles. My chain was last adjusted at 600 miles. It was VERY lose (I could press nearly 2 links up against the chain guard) and it had been running like that for a couple thousand miles. I didn't have the issue the OP is describing though. Only negative was a loss in MPG. I was able to tighten it within spec. Don't think you need a new chain at 10k unless you haven't lubed it once... 
@gigex how many miles were you at when you had your valve clearance serviced?

I did it at 41 500 km (manual says to do it at 42k km), i know thats alot more than 10k miles, but the chain/sprockets haven't shown any signs of significant wear. I'll update this post with a pic of them, maybe i'm a bad judge lol. I clean and lube my chain religiously. every 2 weeks max. I mainly use the bike for commuting.  
I inspected the chain and sprocket last night and was unable to find anything. Slack was within spec, there was no debris around the front sprocket, rims/tyres seem fine.
Also, if it were something to do with chain/sprocket or even tyres/rims, wouldn't the "bob" be felt through each revolution of those? And felt more frequently as you increase speed? I feel it every 5 seconds or so regardless of speed or gear, but not at idle. 

 
 
Once the chain and sprocket are off, you can get a much clearer picture of how worn they really are. Before I changed mine out, on the bike they didn't look very worn, I almost put the maintenance off. Once they were off the bike though the sprockets were much more worn down than they initially appeared.
 
If you are coming up on that maintenance milestone, it's probably worth just doing. You'll be surprised.

[peteinpa]

Is it timed to one rev. of the tire? Some tires can bubble, the tire rubber letting go of the belts. Or a defective tire. Get the wheel off the ground and inspect the tire.

[bugeyes]

Curious about this, please post when you find the reason

[gigex]

Is it timed to one rev. of the tire? Some tires can bubble, the tire rubber letting go of the belts. Or a defective tire. Get the wheel off the ground and inspect the tire.

Nah it's not. I feel it twice in quick succession in the front first, before i feel it under my seat. I checked the rear tyre and seems fine. Can't get the front off the ground (no stand). It's still happening but i've kinda started ignoring it lol. I HAVE noticed tho, that the higher the rpms get the more noticeable it is, not in terms of frequency, but rather force. I have also noticed a pop coming from the exhaust when i close the throttle to shift up (2nd thru 4th gears), not sure if it's related but probably worth mentioning. 

[Zephyr]

Did the bobbing exist prior to the tire replacement? If not, then that is where you should focus your attention, specifically take it back to the dealer and have them thoroughly inspect the front tire for balance and tire rubber itself for imperfections. Also I would inspect the rim myself if I were you to ensure that there aren't any signs of dents, dings, cracks, or otherwise that may indicate that something happened when the tire was replaced.
 
Just thinking out loud here, but... If it was the chain/sprocket, then wouldn't that manifest itself in the rear tire? not through the front end?

[YZEtc]

My only guess is tire/wheel balance being off enough to notice.
The front and rear tires are not the exact same circumference, hence the coming-and-going sensation.

[gigex]

Took the front sprocket cover off a while ago to clean and lube the chain. Normal dirt buildup etc. I cleaned them with kerosene and after scrubbing etc I started hearing this weird clicking noise from the front sprocket. Never heard it before, and not sure it's related, but you can see/hear it in the video below. I'll have the dealer check tyre alignment Saturday
 
https://youtu.be/B1EUNDs2p_4

[bugeyes]

I no longer think it is related to tires, chain or sprockets but air/fuel mix.
You are either running lean or rich on midrange to high revs.
Then unburnt fuel will come out in the exhaust and explode in there, same as lean popping on a poorly jetted carb.
Any wheel or chain issue would be propotional to speed in frequency.

[gigex]

I no longer think it is related to tires, chain or sprockets but air/fuel mix. You are either running lean or rich on midrange to high revs.
Then unburnt fuel will come out in the exhaust and explode in there, same as lean popping on a poorly jetted carb.
Any wheel or chain issue would be propotional to speed in frequency.

 
 
I have a dobeck ejk. The settings are as follows:
 
G:5
Y:6
R:7
GB:4
YB:3.5
RB:1
 
M4 exhaust, k&n air filter, snorkel removed, O2 disconnected, baffle in
 
On initial installation and their settings for the m4 I found it too sluggish so I leaned it out a bit. This was installed in September 2016. Haven't had a problem till now.

[bugeyes]

I bet you are running lean

[gigex]

Been away for a while. Hadn't got chance to update this. But I took the bike in for a routine service they changed fork oil, spark plugs and relubed the suspension link pivot. The bobbing has since stopped. Not sure which of those 3 things was the cause (if any) lol.